Process of etching metal.



No.' 660,262. Patented out. 23,1900.l

c. lMuELLl-:FL

PRDCESS 0F ETCHING METAL.

(Application led July 27, 1900.1

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DEJ/GIV WASI-[5D OUT BY WATER ETCHED.

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UNITED STATES PATENT EEICE.

' CHARLES MUELLER, OF NEW BRITAIN, CONNECTICUT.

PROCESSA oF ETCHING METAII.

SPECIFICATION forming part of Letters Patent No. 660,262, dated october 23, Ieoo.

Application iledJuly 27, 1900. Serial No. 24,970. (No specimens.)

To all whom it may concern:

Be it known that I, CHARLES MUELLER, a citizen of the United States, residing in New Britain, in the county of Hartford and State of Connecticut,have invented certain new and useful Improvements in Processes of Etching Metal, of which the following is a speciiication.

This invention relates to processes of etching designs in metal; and one object of the invention is to provide an improved process of this character by means of which various metals may be quickly and inexpensively provided with designs or trade-marks,the present improved process being particularly adapted for use in applying trade-marks to cutlery.

A further object of the invention is to provide an improved process of this character in which the production of superior designs or trade-marks in metal is obtained with a great deal less skill and care than have heretofore been necessary, while at the same time a deep, particularly clear, and durable design is obtained, so that the metal can be properly polished or burnished without appreciably affecting the quality of the design.

In the present instance this improved process is eXemplied in the drawings in connection with cutlery, although it is understood that it is applicable to all materials which can be etched by acid and is therefore not to be limited to such class of articles.

In the drawings accompanying and forming part of this specification, Figures 1, 3, 5, 7, 9, and l1 illustrate the blade of a knife treated successively by the various successive steps of this improved process, while Figs. 2, .4, 6, 8, l0, and l2 are sectional views taken in lines ct a, respectively, of said first-mentioned iig- UIQS.

Similar characters of reference indicate corresponding parts in the diiierent figures of the drawings.

The present improved process consists in a general way in applying to the article to be ornamented, which may consist of any material which can be etched with acid, a thin ground or rst coat of a suitable varnish adapted to receive and hold the design, which is applied thereto by the use of an alkali solution or composition printed or stamped thereon by some suitable instrumentality. A second varnish highly resistant to acids is then flowed over the article to protect all parts thereof exceptthe d esign,which is then washed outiu some suitable way, and the bared metal corresponding with the design is then subjected to a suitable acid to etch the same.

I am aware that it is not new to apply a ground coat of gum-guaiac varnish to the metal to be ornamented, then printing on such ground coat by a potash or soda composition the design to be etched, and then etching such ornamentation by the application of an acid; but by practical experience with this process I am alsoaware that it has many disadvantages. In such old process the gumguaiac varnish not only acts as the material to receive the imprint of the design, but also as a resist for the acid, so as to protect the metal around the design during the application of the etching material, and as it is nota superior acid-,resisting material consequently thisprocess is unsatisfactory for some cutlers and absolutely of no use for others, since in the first place the gum-guaiac varnish must be applied with great care, for if it is in the least heavy the alkali print will not penetrate to the metal so as to allow the acid to bite into such metal. If, however, the varnish is laid on not quite heavy enough, the resuit is also disastrous, since the varnish will not resist the acid sufficiently long to prevent such acid from eating the metal around the design. Furthermore, another difficulty arises on account of the temperature. In damp Weather a gum-guaiac varnish will dry cloudy and leave many small holes around the stamp or design as the result. In rainy weather or damp days the alkali solution will draw water, and on that account will print in blotted lines, so that this process could not be used at all on manydays of the year on account of its many disadvantages. By my improved process all of these disadvantages are done away with, so thatI am enabled to use the same at all times of thel year regardless of the weather and also with `considerably less care and skill than have heretofore been found necessary. 1 This improved process consists in iirst coating the article to be ornamented, in the present instance shown as a knife-blade 2, with a IOO suitable base coat or layer of material or varnish, and for this purpose I have found that a varnish composed of gum-guaiac and alcohol is preferable, when a suitable antidriersuch, for instance, as fusel oil-is mixed therewith. A very thin coating 3, Figs. l and 2, of this composition is applied to the knifeblade. lBy the use of a very thin layer of this varnish fine hair-line prints can be made with a much smaller percentage of the alkali printing solution, thus doing away with the tendency to blot the lines and characters in damp weather. Without the addition of an antidrier-such, for instance, as fusel-oil- "however, I have found that it is not practicable to use a thin coat of gum-guaiac Varnish, since this thin coat quickly dries and leaves after drying only a powder instead of a varnish, to which, of course, the second varnish which I apply and which acts as a resist to the acid solution would not stick. By the incorporation of fusel-oil with the varnish the drying thereof is delayed, so that a thin coating of this varnish can be applied to the article and will remain thereon in a thin continuous film. On this first coating Bis then printed or stamped the ornamentation or design to be etched, shown herein as a trade-mark It, Figs. 3 and 4, by means of a suitable alkali, such as a potash solution or composition, applied by means of a suitable printing instrumentality-such, for instance, as rubber or flexible type or plates. This alkali printing composition applied to the gum-guaiac varnish combines therewith, the chemical action of such alkali solution and the gum-guaiac varnish having the fusel-oil therein being such that the design can be washed out in some suitable manner, as by the use of water, at the proper time, thereby to bare the metal and permit the acid to bite thereinto. Owing to the many disadvantages which are present when gum-guaiac varnish is used as an acid-resist .I flow over the' metal a second material or varnish of such a composition that it will dry in a smooth continuous layer 5, Figs. 5 and 6. This second varnish not only acts as an acidresist to more thoroughly protect all parts of the article previously covered by the glimguaiac varnish, 4but also protects any part of the article not so covered, so that should the gum-guaiac varnish dry in an imperfect con.- dition i `or with holes therein, owing to the weather or other causes, the second varnish will thoroughly protect the lnetal from-the acid. This second varnish, which acts as the acid resisting layer, preferably comprises bitumen, rosin, and balsam-iir dissolved in turpentine and benzol. This forms a composition which not only resists the acid, which may be used of double the ordinary strength as compared with that which it has heretofore been possible to use with a guaiac varnish constituting the protection for the metal, but it is also proof against the water which may be employed for washing out the design. This composition is fiowed over the varnish- The use of fusel-oil in the gum-guaiac varnish combines with the alkali printing comq position in such manner, it is believed, as to assist in causing the second coating of varnish to recede from the design in the manner set forth. The design is then etched in the metal, Figs. 9 and 10, by the use of a suitable acid-'as, for instance, nitric acid--combined with water in some suitable manner, after which the acid-resisting coating is removed, Figs. ll and 12, and the knife polished or burnished in the usual way, and which polishing can then be done without appreciably affecting the quality of the design, Which has heretofore been a difficult matter to accomplish. In practice I have found that, even with the additional time required to apply the second Varnish or acidresisting coating, a very much larger number of knives can be etched per-day with this improved process, since comparatively little skill is required to do the work, than can be etched by the use of the process heretofore patented, since considerable skill and care were required in order to secure results which were much less perfect and desirable than those obtained by the use ot' this improved process.

As above set forth, owing to the fact that I am able to use a second varnish which more effectively resists the action of the acid I can use acid twice as strong as that used with other methods in vogue, and consequently the etching of the metal is much deeper, so that when the metal is burnished the design will not be appreciably affected.

Before the application of the acid the metal which has been bared by the washing out of the design may be dried in some suitable inanner, if desired, whereby on the application of the acid such acid will not be neutralized by the water remaining on the metal and which was used to Wash out the design.

Having thus described my invention, what I claim is 1. The process of etching designs in metal, which consists in first coating the metal with a material adapted to act as a base for the design; then printing the design on such coat; then flowing the metal with an acid-resisting material adapted to protect all parts of the metal except the design; and then etching such design in the metal.

2. The process of etching designs in metal,

which consists in first coating the metal with a material adapted to act as a base for the design; then printing the design on such coat;

`then flowing the metal with an acid-resisting IOO 'material adapted to protect all parts of the metal except the design; then Washing ont such design to barerthennietal corresponding therewith; and then etching the same.

3. The process'of etching designs in metal7 which consists in first coating the metal with a material adapted to act as a base for the design; then printing the design on such coat with a material adapted to combine With the material of such coat; then owing the metal With an acid-resisting material adapted to protect all parts of the metal except the design; then washing ont such design to bare the metal corresponding therewith; and then etching the same.

4E. The process of etching designs in metal, Which consists in coating the metal With a gnm-guaiac varnish; then stamping the design therein by the use of an alkali composition; then protecting all parts of the metal except the design by an acid-resisting varnish; then Washing out the design to bare the plate corresponding therewith; and then etching the design in the plate.

5. The process of etching designsin metal, which consists in coating the metal with a gum-guaiac varnish; then stamping the design thereon bythe use of an alkali composition; then protecting all parts of the metal except the design by an acid-resisting varnish comprising bitumen, rosin, and balsamtr dissolved in turpentine and benzol; then Washing ont the design; and then etching the bared metal by the use of an acid.

6. The process of etching designs in met-al, which consists in first coating the metal With a thin layer of Varnish having an antidrier incorporated therein; then stamping thereon the design; then applying a protecting-coating to such article thereby to protect all parts thereof except the design; then Washing out the design; and then etching the bared metal.

7. The process of etching designs in metal,

which consists in first coating themetal with a varnish having fnsel-oil incorporated therein; then stamping thereon the design by the use of an alkali composition; then protect= ing all parts of the article except the design by a second varnish coating; fthen Washing out the design; and then etching the bared metal.

8. The process of etching designs in metal, which consists in` first coating the metal with gum-gnaiac varnish having fusel-oil incorporated therein; then stamping the design thereon by theuse of an alkali composition; then protecting all parts of the metal except the design by a second varnish coating; then washing ont the design; bared metal.

9. The process of etching designs in metal, which consists of applying thereto acoating of gum-gnaiac Varnish having fusel-oil incorporated therein; then stamping thereon the design by the application of a potash solution; then protecting the metal around such design by the application of a varnish coating comprising bitumen, rosin, and balsamfrr dissolved in turpentine and benzol; then washing out such design; and then etching the metal to correspond With such design.

l0. The process of etching designs in metal,

and then etching the l which consists in coating the metal-With gnm- Witnesses:

LoREN D. PENFIELD, GEORGE W. KLETT. 

